1. Field of the Invention
The present invention relates to thermal printers having a separate paper feeder and printer casing, the paper feeder being attached to the casing to be openable and closable.
2. Description of the Prior Art
In this type of thermal printer, as disclosed in Japanese Patent Publication Kokai No. 58-140272, for example, a separating roller is pressed against a platen roller. In this thermal printer, an ink ribbon may become creased for the following reasons:
(1) When patterns to be transferred vary to a great extent transversely of the ink ribbon, creases are formed on the ink ribbon during transportation thereof from a transfer position to a separating position since ink fixation and deformation of the ink ribbon due to the heat are not uniform transversely of the ink ribbon.
(2) When the platen roller and the separating roller are not parallel, creases are formed during transportation of the ink ribbon from the transfer position to the separating position during printing on an elongate sheet such as an A3 size sheet.
In the known printer in which the separating roller and the platen roller are in pressure contact, the creased ink ribbon is transported to the separating roller. Consequently, the ink ribbon having the creases advances to the transfer position to the detriment of the transfer operation.
In order to solve this problem it is conceivable to maintain the separating roller out of contact with the platen roller. However, the two rollers cannot be spaced wide apart due to characteristics of the ink employed. This results in the problem of interference between the platen roller and the separating roller occurring when the paper feeder is opened for changing the ink ribbon cassette, for example.